"I don't just mean a referndum on Europe - though, naturally, that is the obvious place to start. I mean full-on Helvetic people power... I have returned to the back benches in order to concentrate on building such a movement."

Mr Hannan added that his decision was not an attack on Mr Cameron's decision to no longer hold a Lisbon Treaty referendum.

"Don’t misunderstand me: I voted for David Cameron as leader, I like him, and I reckon he’d be a million times better than Gordon Brown as Prime Minister. One of his strengths is that, unlike Gordon Brown, he doesn’t mind people disagreeing with him," he wrote.

"Well, then. This Conservative is for a referendum: a proper, deep-cleansing referendum that will settle whether our country remains subordinate, or becomes self-governing."

Mr Hannan caused controversy earlier this summer when he launched a blistering attack on the NHS, telling US TV station Fox News that it was a "relic".